Coordination versatility in palladium(II) complexes bearing substituted naphthoylthioureas: crystal structures, Hirshfeld surface analysis, DFT and molecular docking studies
Year: 2026
Type: article
Abstract: Two ligands derived from N , N -dipropyl- N ′- 1/2 -naphthoylthiourea (HL 1,2 ) and their corresponding cis ‑palladium(II) complexes are synthesized and characterized using 1 H NMR, FT-IR, and elemental analysis. Single-crystal X-ray diffraction studies reveal that the 2 -naphthyl-substituted (HL 2 ) ligand afforded a neutral bis-chelated cis -[Pd(L 2 - S , O ) 2 ] complex, upon crystallization from dichloromethane/hexane, whereas crystallization from methanol/chloroform yielded a monoligated [Pd(L 2 - S , O )(L 2 - S )( Cl )] complex. In contrast, the 1 -naphthyl-substituted (HL 1 ) ligand exclusively forms the neutral cis -[Pd(L 1 - S , O ) 2 ] complex. Hirshfeld surface analysis show that H⋯H, C⋯H, N⋯H, O⋯H, and H⋯Cl interactions constitute the dominant contributions to the crystal packing in the isolated cis -[Pd(L 1,2 - S , O ) 2 ] and [Pd(L 2 - S , O )(L 2 - S )( Cl )] complexes. Density functional theory (DFT) calculations reveal that the frontier molecular orbitals are delocalized over the Pd(II) coordination sphere and the conjugated acylthiourea ligand backbone, with HOMO–LUMO energy gaps in the range 4.24–4.38 eV, and the largest gap determined for [Pd(L 2 - S , O )(L 2 - S )( Cl )]. Molecular docking studies with DNA gyrase indicate stronger binding affinities for the bis-chelated cis -[Pd(L 1.2 - S , O ) 2 ] structures compared to the mono-ligated [Pd(L 2 - S , O )(L 2 - S )( Cl )] complex, dominated by hydrogen bonding and hydrophobic interactions.
Source: Results in Chemistry
Language: English
Subfield: Inorganic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,870
OpenAlex ID: W7212050952